I buy cheap 52mm condoms and I think they are too small for me. When I'm fully erect I cannot unroll them over my dick which is why I put them on when I'm limb or not fully erect and then when I get hard they sit very tight and they actually work. But when I remove the condom later on then I have like an imprint on my shaft from the ring of the condom cause my dick isn't long enough to unroll it completely and because of this there's always a firm ring at the base which consists of the unrolled condom.

I wonder could this damage the penis? Could this be similar to wearing a tight cock ring? Cause cock rings shouldn't be worn longer than 20 minutes or so but when I masturbate with sex toys then I usually have it on much longer than 20 minutes.

It seems that if the condom were too tight, it would act like a tourniquet which reduces the blood flow. If you are getting an erection, the blood flow has not been cut off. That said, you might want to try a magnum size and see if it is any more comfortable.

Keep in mind, though, that it is not unusual that you can't unroll the condom completely.

It does sound like you could do with a larger size. Different condom sizes are to handle differences in girth: as readytogo pointed out, they are all made to handle almost any length, because fully unrolled they are much longer than the average penis. So nearly every guy doesn't unroll it completely.

But if you can't unroll it when fully erect then I think you may need a larger size: you may be thicker than average. Certainly worth trying out.

I'm not sure. Should a condom if it has the right size unroll over the penis without having to use
any force? The 52mm condom which I use require force when I want to unroll them. However once
they are on and I'm fully hard they fit and stay on and don't roll back and forth. This is an issue I had
with bigger condoms they would just move back and forth which really sucked.

It should take minimal force to roll a condom on, because the point is for it to stay on until you're ready to unroll it. There's no problem with the middle of the condom being loose (and rolling back and forth) as long as the rolled end remains firmly on the penis.